Lower Elementary:
Question: Calvin and Alex raced each other in go-carts. Calvin finished the first lap in 45 seconds, the second lap in 50 seconds, and the third lap in 40 seconds. Alex finished the first lap in 47 seconds, the second lap in 44 seconds, and the last lap in 43 seconds. Who won the race?
Answer: Alex
Solution: First, we need to calculate how long it took Calvin and Alex to finish the race separately. Calvin’s lap times were 45 seconds, 50 seconds, and 40 seconds. 45 + 50 + 40 = 95 + 40 = 135 seconds. Alex’s lap times were 47 seconds, 44 seconds and 43 seconds. Notice that it may be easier to add 47 and 43 together since their one’s place adds to 10. 47 + 44 + 43 = 90 + 44 = 134. So Calvin finished the race in 135 seconds and Alex finished the race in 134 seconds, so Alex won the race.
Upper Elementary:
Question: Jessica can type 30 words per minute. She needs to type a total of 500 words. If she has already typed 80 words, how much longer will it take Jessica to finish typing all of the words?
Answer: 14 minutes
Solution: First, we need to find out how many more words Jessica has left to type. 500 – 80 = 420. Jessica has 420 more words to type. Since she types 30 words per minute, divide the total number of words left to type by Jessica’s typing speed to see how much longer it will take. 420 ÷ 30 = 14. It will take Jessica 14 minutes to finish the typing.
Middle School:
Question: Dom has two options. He can either purchase a $25 shirt in store or he can order the same shirt online for a 20% discountand pay an additional $5.75 for shipping and handling. What is the better buy and by how much?
Answer: Purchasing in store, Dom saves 75¢
Solution: We know how much the shirt in the store costs, so we have to find out the cost of the shirt online. First we have to find 20% of $25 to find out how much the discount is. Percent means for each hundred, and since 20 is 1/5 of 100, to find 20% of $25, divide by 5. 25 ÷ 5 = 5. So, the discount is $5. This means that the shirt costs $20 online (25 – 5 = 20). However, with the shipping and handling cost, the shirt is $25.75 if purchased online (20 + 5.75 = 25.75). So it is cheaper if Dom buys the shirt in the store because he saves 75¢.
Algebra and Up:
Question: What is the probability of rolling three 6-sided dice and getting a sum of 3 or 18?
Answer: 2/216 = 1/108
Solution: First we need to find the total number of outcomes there are for rolling three 6-sided dice. Multiply the number of outcomes for each die together to get the total number of outcomes. 6 × 6 × 6 = 216. There are 216 different options. There is 1 way of rolling a sum of a three (1, 1, 1) and only 1 way of rolling a sum of 18 (6, 6, 6). So the probability of rolling a sum of 3 or 18 with three 6-sided dice is 2/216 = 1/108.
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